Battery-Operated and Self-Heating Solid-Phase Microextraction Device for Field Detection and Long-Term Preservation of Mercury in Soil

Abstract

The application of headspace solid-phase microextraction (HS-SPME) for mercury preservation and detection still has several shortcomings, including the use of high-temperature desorption chamber, the consumption of expensive reagent (NaBEt 4 or NaBPr 4 ), and analyte loss during sample storage. Herein, a self-heating HS-SPME device using a gold-coated tungsten (Au@W) fiber was developed for the field detection of mercury in soil by miniature point discharge optical emission spectrometry (μPD-OES). Hg 2+ was reduced to Hg 0 with NaBH 4 solution and then preconcentrated with the Au@W fiber. The adsorbed Hg 0 could be rapidly desorbed by directly heating the fiber with a mini lithium battery and subsequently detected by μPD-OES. A limit of detection (LOD) of 0.008 mg kg −1 was obtained with a relative standard deviation (RSD) of 2.4%. The accuracy of the self-heating HS-SPME was evaluated by analyzing a soil certified reference material (CRM) and nine soil samples with satisfactory recoveries (86−111%). Compared to the conventional external heating method, the proposed method reduces desorption time and power consumption from 80 s and 60 W to 20 s and 2.5 W, respectively. Moreover, the self-heating device enables the μPD-OES system to remove the high-temperature desorption chamber, making it more compact and suitable for field analytical chemistry. Interestingly, the Au@W SPME fiber can be also used for the long-term preservation of mercury with a sample loss rate <5% after 30 days of storage at room temperature.

Atomic spectrometry update: review of advances in atomic spectrometry and related techniques

“…Azooz et al 10 reviewed LPE and SPE for the determination of Se, in particular the use of supramolecular solvents, hydrophobic deep eutectic solvents (DESs), and ionic liquids (ILs). Wang et al 11 developed a battery-operated, SPME device for field analysis of Hg. The Au@W SPME fibre extraction device was fabricated from tungsten wire coil, electro-plated with gold and inserted into a sample vial.…”

Direct and Sensitive Detection of Mercury in Soil by Portable Electromagnetic Heating Vaporization and Purge-and-trap Followed by Microplasma Optical Emission Spectrometry

“…10 Consequently, substantial efforts have been devoted to developing methods for detecting mercury in soil. [11][12][13] Techniques such as laser-induced breakdown spectroscopy (LIBS) 14,15 and X-ray Fluorescence Spectrometry (XRF) 16,17 are popular due to their cost-effectiveness, minimal sample preparation, and rapid on-site detection capabilities. However, these methods often suffer from low sensitivity, serious matrix interference, and a lack of solid certified reference materials (CRMs) with matching matrices, rendering them unsuitable for rapid screening of heavy metals in soil samples.…”

“…Recently, several types of microplasmas have been used to develop compact optical emission spectrometers for field detection of heavy metals. These systems are characterized by their small size, high excitation capability, and low power consumption, including liquid electrode glow discharge (LEGD), [26][27][28][29] point discharge (PD) , 11,[30][31][32] dielectric barrier discharge (DBD), 22,[33][34][35] atmospheric pressure glow discharge (APGD), [36][37][38] and solution cathode glow discharge (SCGD). 39,40 Despite their proven feasibility for elemental detection and significant performance improvements when coupled with efficient sampling techniques, 11,30 they have primarily been utilized for environmental water sample analysis due to minimal or no sample pretreatment requirements.…”

“…These systems are characterized by their small size, high excitation capability, and low power consumption, including liquid electrode glow discharge (LEGD), [26][27][28][29] point discharge (PD) , 11,[30][31][32] dielectric barrier discharge (DBD), 22,[33][34][35] atmospheric pressure glow discharge (APGD), [36][37][38] and solution cathode glow discharge (SCGD). 39,40 Despite their proven feasibility for elemental detection and significant performance improvements when coupled with efficient sampling techniques, 11,30 they have primarily been utilized for environmental water sample analysis due to minimal or no sample pretreatment requirements. A recent development includes a simple, low-power-consuming online digestion unit integrated with a portable PD optical emission spectrometer for detecting Pb in rice and solid biological samples in rice and some solid biological samples 41 .…”

Handheld Microplasma Optical Emission Spectrometer Coupling With Self-Heating Solid-Phase Microextraction For On-Site Detection Of Urinary Lead

“…To solve these problems and improve analytical performance, the MP-OES has been coupled with many sample introduction techniques, including cold vapor generation, 22 hydride generation, 18 photochemical vapor generation, 23 tungsten coil (Wcoil) electrothermal vaporization, 24,25 and solid-phase microextraction (SPME). 21,[26][27][28] These sampling approaches can efficiently separate analytes from liquid phase as "dry" species before their exposure to microplasma, significantly enhancing the MP-OES sensitivity and alleviating matrix interferences. Among these methods, SPME is the most suitable for MP-OES because it can integrate the separation, preconcentration, and sample introduction of analytes from complex sample matrices into a single step.…”